This invention relates to hopper door assemblies for opening and closing openings in hoppers for particulate matter such as feed hoppers and in particular to such hopper door assemblies that are adaptable to a number of different types of hopper door controls.
In the past, it has been common for most hopper manufacturers to design a hopper door assembly for one particular type of closure apparatus, and therefore to design separate and different hopper door assemblies for the various different types of closure apparatus available. For instance, Blout, U.S. Pat. No. 4,342,267, shows a hopper door closure assembly that is opened and closed by turning a shaft, that shaft having thereon pinions which engage perforations forming a rack. As another example, Johnson, U.S. Pat. No. 4,359,176, shows a hopper door closure assembly wherein the door is closed by a power actuator cylinder.
The generally accepted idea in the industry, that separate models of doors are required to accommodate the different types of closures, requires the manufacturer and retailer to carry high numbers of inventory items. There is need in the market, then, for a hopper door closure assembly that is adaptable to a number of different types of closures, and which in addition is highly resistant to leaking dust from the assembled hopper into the surrounding air. Further, it is desirable to provide the capability to easily convert from one type of closure to another after installation of the hopper door and closure assembly.
This invention relates to improvements to the apparatus described above and to solutions to the problems raised or not solved thereby.